Daidzein has both weak estrogenic and weak anti-estrogenic effects. Daizein has also antioxidant activity.

Foti P. et al of the Department of Food Science and Microbiology (University of Milan) compared the antioxidant activity daidzein and genistein.antioxidant activity in primary and cancer lymphocytes. Their results showed that daidzein is just as effective as genistein in protecting cells against oxidative damage of DNA. The antioxidant activity of daidzein was measured at concentration which could be obtained by consumption of soy products.